1. Why does he need to equalise his ears on the way down? What would happen if he just shot up to the surface from 20m down?

2. Objectives Relate (without calculation) the pressure beneath a liquid surface to depth and to density, using appropriate examples. Recall and use the equation p = F/A Recall and use the equation p = hρg Outcomes C: Describe how to calculate pressure. B: Calculate pressure in different situations using both equations. A: Calculate pressure in complex situations using a series of steps. Key terms: Pressure, force, area, density, equation.

3. Task Calculating your pressure on an area. Using the equation P = F / A Calculate your pressure on an area. What would the units be? Outcomes C: Describe how to calculate pressure. B: Calculate pressure in different situations using both equations. A: Calculate pressure in complex situations using a series of steps. Key terms: Pressure, force, area, density, equation. Pressure is measured in Newton's per square meter (N/m 2 ) also known as Pascal's (Pa) – it can also be measured in N/cm 2

4. Key terms: Pressure, force, area, density, equation.

5. P = hpg where h is depth of fluid, g is gravitational field strength, and p is the density (mass per unit volume) Calculate the pressure on an object 10m down in water (density: 1000kg/m 3 ). Outcomes C: Describe how to calculate pressure. B: Calculate pressure in different situations using both equations. A: Calculate pressure in complex situations using a series of steps. Key terms: Pressure, force, area, density, equation.

6. A 0.75-kg physics book with dimensions of 24 cm by 20 cm is on a table. What force does the book apply to the table? What pressure does the book apply? The pressure exerted by the atmosphere is about 1.0 x 10 5 Pa. Convert this to kPa. A 75-kg solid cylinder, 2.5 m long and with an end radius of 5.0 cm, stands on one end. How much pressure does it exert? A reservoir behind a dam is 15 m deep. What is the pressure at the base of the dam? What is the pressure 5.0 m from the top of the dam? How tall must a column of mercury, d = 1.36 x 10 4 kg/m 3, be to exert a pressure equal to the atmosphere? A dog, whose paw has an area of 12.0 cm, has a mass of 8.0 kg. What average pressure does the dog exert while standing? A crate, whose bottom surface is 50.4 cm by 28.3 cm, exerts a pressure of 2.50 x 10 3 Pa on the floor. What is the mass of the crate? A test tube standing vertically in a test- tube rack contains 2.5 cm of oil (d = 0.81 g/cm 3 ) and 6.5 cm of water. What is the pressure on the bottom of the test tube?